Method for sanitizing toilets

ABSTRACT

A method for sanitizing toilets wherein a hypochlorite sanitizing agent and an oxidizable dye are dispensed from separate dispensing means into the toilet flush water to provide a color to the bowl water. The color disappears within a short time after the flush, thereby providing a visual indicator of the activity of the sanitizing agent.

TECHNICAL FIELD

The present invention relates to the automatic sanitizing of flushtoilets by the dispensing of a bleachable dye and a hypochloritesanitizing agent to the toilet bowl with each flush. The dye is bleachedby the hypochlorite to a colorless state within a short time afterflushing, thereby providing a visual signal of the activity of thehypochlorite.

BACKGROUND ART

This invention relates to a method of sanitizing a toilet bowl. Moreparticularly, it relates to a method wherein a hypochlorite sanitizingagent and a water-soluble dye, which is oxidizable by the hypochloritefrom a colored to a colorless state, are automatically dispensed fromseparate dispensing means to the toilet bowl during flushing. The waterin the bowl at the end of the flush is colored by the dye. However, thedye is oxidized to a colorless state within a short time therebyproviding a visual signal that the hypochlorite sanitizing agent ispresent and "acting" in the bowl.

Automatically dispensed toilet bowl cleaning and/or sanitizing products,which contain dyes to provide a visual signal to the user that productis being dispensed, are well known. Such products are sold in the UnitedStates under the brand names VANISH AUTOMATIC (Drackett Products),TY-D-BOL AUTOMATIC (Knomark, Inc.) and SANIFLUSH AUTOMATIC(Boyle-Midway). None of these products contains a hypochloritesanitizing agent and all of them provide a color to the bowl water whichpersists between flushings. U.S. Pat. No. 3,504,384, Radley et al.,issued Apr. 7, 1970, discloses a dual compartment dispenser forautomatically dispensing a hypochlorite solution and a surfactant/dyesolution to the toilet bowl during flushing. The dye which is taught inthe patent is Disulfide Blue VN150. It is believed that the dye referredto in Radley et al. is actually Disulphine Blue VN150 (Color Index No.42045). This dye has been found by the present applicant to be quiteresistant to oxidation to a colorless state by hypochlorite; thus, ittoo provides a persistent color to the toilet bowl water, even in thepresence of the hypochlorite.

A persistent color in the toilet bowl water has certain attendantnegatives. The dye can cause staining of the toilet bowl itself or ofdeposits (such as water hardness deposits) which accumulate on thesurfaces of the bowl between manual cleanings. Also, colored water inthe bowl will tend to obscure medical symptoms such as the passing ofblood during excretion or urination. Further, a persistent color in thetoilet bowl water tends to obscure otherwise visible evidence of soilingon surfaces of the toilet bowl which are below the water line.

An object of the present invention is to provide a method ofautomatically sanitizing a toilet bowl with each flush.

Another object of the invention is to provide a visual color signal toindicate that the sanitizing agent is present and acting in the toiletbowl.

Another object of the invention is to provide a visual color signalwhich persists in the toilet bowl for only a short time after flushing.

Another object of the invention is to provide, by a visual color signal,a means by which the consumer will know when a new supply of sanitizingagent needs to be provided for the toilet.

DISCLOSURE OF INVENTION

The present invention relates to a method of treating a flush toilet,which comprises a flush tank and bowl, with a hypochlorite sanitizingagent each time the toilet is flushed, and providing a transitory visualsignal to indicate the activity of the sanitizing agent in the bowl. Thesaid method comprises the step of dispensing from separate dispensingmeans, into the flush water; (A) an aqueous solution of a compound whichproduces hypochlorite ion in aqueous solution; and (B) a solution of adye, the said dye being one which is oxidized from a colored state to acolorless state in the bowl within about 5 seconds to 10 minutes(preferably about 10 seconds to about 5 minutes) after contact with thehypochlorite. If desired, the dye solution can also contain awater-soluble bromide salt to catalyze the activity of the hypochlorite.

The Sanitizing Agent

The sanitizing agent of the present invention can be any compound whichprovides the hypochlorite ion (OCl⁻) in aqueous solution. Such compoundsinclude alkali metal and alkaline earth metal hypochlorites,hypochlorite addition products, chloramines, chlorimines, chloramides,and chlorimides. Specific examples of compounds of this type includesodium hypochlorite, potassium hypochlorite, lithium hypochlorite,calcium hypochlorite, calcium hypochlorite dihydrate, monobasic calciumhypochlorite, dibasic magnesium hypochlorite, chlorinated trisodiumphosphate dodecahydrate, potassium dichloroisocyanurate, sodiumdichloroisocyanurate, sodium dichloroisocyanurate dihydrate,1,3-dichloro-5,5-dimethylhydantoin, N-chlorosulfamide, Chloramine T,Dichloramine T, Chloramine B, Dichloramine B, and Di-Halo(bromochlorodimethyl hydantoin). A particularly preferred sanitizingagent composition suitable for use in the practice of the presentinvention is described in the commonly assigned U.S. patent applicationof John Daniel Nyquist entitled DISINFECTING COMPOSITION, Ser. No.897,478, filed Apr. 18, 1978, said patent application being incorporatedherein by reference. The composition described in the Nyquistapplication is a compacted cake comprising lithium hypochlorite andcalcium hypochlorite in a ratio of lithium hypochlorite:calciumhypochlorite of from about 0.58:1 to about 0.17:1, by weight.

By virtue of the strong oxidizing power of the hypochlorite ion, it ishighly effective in bleaching stains, breaking down and removing soilsand killing microorganisms, thereby providing effective sanitizingaction to the toilet bowl.

The amount of hypochlorite-providing compound dispensed to the toilet inthe process of the invention can vary over a wide range, but preferablyshould be sufficient to provide from about 2 to about 30 ppm (preferablyfrom about 4 to about 8 ppm) available chlorine in the bowl water at theend of the flush. Only a very small amount of the available chlorinewhich is delivered to the bowl will be utilized in oxidizing the dye.The sanitizing agent can be formulated as an aqueous liquid if it is tobe dispensed from a dispensing means designed to receive liquids. Thesanitizing agent can also be formulated into the form of a solid cakefor use in dispensing means which are designed to receive a cake ofsolid material (see description of dispensing means below). The level ofavailable chlorine in the bowl water can be measured by well-knownmethods such as the DPD Ferrous Titrametric Method or the StabilizedNeutral Orthotolidine Method, described, respectively, at pages 129 and126 of Standard Methods for the Examination of Water and Wastewater,13th Ed., published by American Public Health Association.

If desired, the activity of the hypochlorite can be catalyzed byaddition of bromide ion to the process of the invention. This willenhance the sanitizing activity of hypochlorite in the toilet bowl, andwill speed up the oxidation of the dye. Generally, any compound whichproduces bromide ion in aqueous solution can be used as the source ofbromide ion. Examples of such compounds are inorganic bromide salts suchas sodium bromide, potassium bromide, calcium bromide, zinc bromide,magnesium bromide and lithium bromide, as well as organic salts such ascetylpyridinium bromide and cetyltrimethylammonium bromide. The bromidesalt is kept separate from the hypochlorite sanitizing agent until thesanitizing agent is dispensed into the flush water, i.e., the bromideand sanitizing agent are dispensed from separate dispensing means.Preferably, the bromide salt is dispensed to the toilet from the samedispensing means as the dye. When a bromide catalyst is used, the amountwhich is used preferably should be sufficient to provide a weight ratioof available chlorine to bromine ion of from about 2:1 to about 150:1,and most preferably from about 4:1 to about 13:1 in the toilet bowl.(All percentages and ratios herein are "by weight" unless specifiedotherwise.)

Dyes

A water-soluble bleachable dye is an essential feature of the presentinvention. The dye should be soluble in water to the extent of at least0.01% by weight in water at 25° C.

The amount of dye dispensed to the toilet in the process of theinvention will depend on the color intensity desired, the amount ofsanitizing agent dispensed into the toilet with the dye, and on thequickness with which it is desired to have the color disappear.Generally, the amount of dye dispensed will be sufficient to produce adye concentration of from about 0.02 to about 2 ppm, preferably fromabout 0.2 ppm to about 1.5 ppm in the toilet bowl. Generally, the dyeshould be present in a ratio of available chlorine:dye of from 2:1 toabout 150:1, preferably from about 5:1 to about 25:1. Dye concentrationand ratios herein are based upon the amount of the actual dye compound,unless specified otherwise. Dyes are normally sold in the form ofmixtures of dye compound and inert diluent.

Dyes which are suitable for use in the method of the present inventionare those which are oxidized by the sanitizing agent to a colorlessstate within a period of from about 5 seconds to 10 minutes from thetime they come into contact with the sanitizing agent during theflushing of the toilet. A wide variety of oxidizable dyes can beutilized in the present process.

The following screening test can be used for determining the suitabilityof any particular dye for use in the method of the present invention.The test is conducted at pH 6 and pH 9, since this represents the rangeof pH's likely to be found in tap water.

Three liters of deionized water at 65° F. are placed in a four literbeaker, and the water is kept in stirring motion with a magneticstirrer. 65° F. was chosen because it is approximately the mediantemperature for toilet flush water, which generally can vary in therange of 40° F. to 80° F. The appropriate amount of sodium hypochloriteis added via a pipette to the water from a 1% available chlorine aqueousstock solution of sodium hypochlorite. The pH is then adjusted to 6 or 9with a one percent aqueous solution of NaOH or H₂ SO₄, as needed. Ifbromide catalysis is utilized, the appropriate amount of sodium bromideis added from an aqueous stock solution (1% NaBr in water). The colorchange reaction is initiated by the addition of the appropriate amountof a stock solution of dye (0.1% dye, on an "as received" basis, inwater). The solution is then observed to determine the time fordisappearance of color.

The following table presents data on the testing of various dyes forsuitability for use in the present invention with an available chlorinelevel of 5 ppm, catalyzed with 1.0 ppm bromide ion, and uncatalyzed. Thedye level in all instances was 1 ppm on an "as received" basis. Basedupon information provided by suppliers of the dyes, the approximateconcentrations of actual dye were calculated and are shown in the table.The table records the time interval (M=minutes, S=seconds) from when thedye solution is added until the color disappears in the breaker.

                  TABLE I                                                         ______________________________________                                               pH 6          pH 9                                                                           5 ppm           ppm                                          Conc.   5 ppm    Av. Cl.sub.2                                                                           5 ppm  Av. Cl.sub.2                            Dye* ppm     Av. Cl.sub.2                                                                           1.0 ppm Br.sup.-                                                                       Av. Cl.sub.2                                                                         1.0 ppm Br.sup.-                        ______________________________________                                        1    0.92    >10 M    >10 M    >10 M  >10 M                                   2    0.90    >10 M    >10 M    6 M    15 S                                    3    0.88    >10 M    >10 M    >10 M  >10 M                                   4    0.68    >10 M    >10 M    >10 M  >10 M                                   5    0.95    >10 M    1 M      8 M    1.3 M                                   6    0.25    1 M      4 M      6 M    15 S                                    7    0.90    >10 M    9 M      2 M    1.5 M                                   8    1.0     4.5 M    2.5 M    1.8 M  1.8 M                                   9    0.13    >10 M    3.5 M    7 M    1 M                                     10   0.29    1.5 M    10 S     8 M    1.5 M                                   11   0.85    6 M      2 M       >10 M 3 M                                     12   0.75    >10 M    3.5 M    6 M    1.5 M                                    *Dye identification (C.I. refers to the Color Index listing name or           number)                                                                  

    1   FD&C Blue #1        C.I. 42090                                            2   FD&C Blue #2        C.I. 73015                                            3   FD&C Green #3       C.I. 42053                                            4   Disulphine Blue VN  C.I. 42045                                            5   Alizarine Light Blue B                                                                            C.I. 63010                                            6   Carta Blue VP       C.I. 24401                                            7   Acid Green 2G       C.I. 42085                                            8   Astrazon Green D    C.I. 42040                                            9   Supranol Cyanine 7B C.I. 42675                                            10  Maxilon Blue 3RL    C.I. Basic Blue 80                                    11  Drimarene Blue Z-RL C.I. Reactive Blue 17                                 12  Alizarine Light Blue H-RL                                                                         C.I. Acid Blue 182                                    ______________________________________                                    

From these data it can be seen that for uncatalyzed hypochlorite at 5ppm Av. Cl₂, dyes 6, 8, and 10 provide a color-to-colorless signal inthe required time frame at both pH's. For bromide-catalyzed hypochloriteat 5 ppm Av.Cl₂ and 1 ppm bromide, dyes 5, 6, 7, 8, 9, 10, 11, and 12provide a color-to-colorless signal in the required time frame at bothpH's.

Optionally, the dyes used in the method of the present invention can beformulated into compositions containing other ingredients which it isdesired to dispense into the toilet bowl, such as, for example,surfactants, sequestering agents, perfumes, and diluents such as water,organic solvents such as ethanol, and organic or inorganic salts such assodium sulfate, sodium chloride and sodium acetate.

Surfactants can provide enhanced sanitizing performance through breakupand emulsification of soils, and also provide some sudsing in the toiletbowl, which may be aesthetically desirable. Perfumes provide a pleasantsmell to the area surrounding the toilet and also help to obscure the"bleach" smell of the sanitizing agent. Sequestrants aid soil removal bysequestration of multivalent metal ions.

When the dyes herein are formulated with surfactants, the resultingcompositions will generally comprise from about 5% to about 99%surfactant and from about 0.2% to about 15% dye. Perfumes will normallybe used at levels of up to about 25% and inert diluents at levels up toabout 90%. Sequestering agents such as potassium pyrophosphate, sodiumtripolyphosphate and ethylenediamine pentaacetate can be used at levelsup to about 25%.

Compositions comprising the dye and a surfactant and/or otheringredients can be conveniently pressed into the form of a cake for usein dispensers which are designed to receive a cake of solid material(see description of dispensing means, below). Such cakes can be made byextrusion or hydraulic stamping, or by pouring a melt of the compositioninto a mold and solidifying the composition by cooling.

If it is desired to use a dispensing means which is designed to receiveliquids, the dye and any optional ingredients such as surfactants, etc.,can be formulated into liquid compositions.

Dyes 8 and 10 in Table I are cationic dyes, whereas the remainder areanionic. When surfactants are to be used in the present invention, it isimportant that dye and surfactant be selected so as to be compatiblewith each other. Cationic dyes should not be used with anionicsurfactants, and anionic dyes should not be used with cationicsurfactants.

Anionic surfactants operable in compositions suitable for use inpracticing the present invention can be broadly described as thewater-soluble salts, particularly the alkali metal salts, of organicsulfuric acid reaction products having in their molecular structure analkyl or alkaryl radical containing from about 8 to about 22 carbonatoms and a radical selected from the group consisting of sulfonic acidand sulfuric acid ester radicals. (Included in the term alkyl is thealkyl portion of higher acyl radicals.) Important examples of theanionic surfactants which can be employed in the practicing of thepresent invention are the sodium or potassium alkyl sulfates, especiallythose obtained by sulfating the higher alcohols (C₈ -C₁₈ carbon atoms)produced by reducing the glycerides of tallow or coconut oil; sodium orpotassium alkyl benzene sulfonates, in which the alkyl group containsfrom about 9 to about 15 carbon atoms, (the alkyl radical can be astraight or branched aliphatic chain); paraffin sulfonate surfactantshaving the general formula RSO₃ M, wherein R is a primary or secondaryalkyl group containing from about 8 to about 22 carbon atoms (preferably10 to 18 carbon atoms) and M is an alkali metal, e.g., sodium orpotassium; sodium alkyl glyceryl ether sulfonates, especially thoseethers of the higher alcohols derived from tallow and coconut oil;sodium coconut oil fatty acid monoglyceride sulfates and sulfonates;sodium or potassium salts of sulfuric acid esters of the reactionproduct of one mole of a higher fatty alcohol (e.g., tallow or coconutoil alcohols) and about 1 to 10 moles of ethylene oxide; sodium orpotassium salts of alkyl phenol ethylene oxide ether sulfates with about1 to about 10 units of ethylene oxide per molecule and in which thealkyl radicals contain from about 8 to about 12 carbon atoms; thereaction products of fatty acids esterified with isethionic acid andneutralized with sodium hydroxide where, for example, the fatty acidsare derived from coconut oil; sodium or potassium salts of fatty acidamides of a methyl tauride in which the fatty acids, for example, arederived from coconut oil and sodium or potassium β-acetoxy- orβ-acetamido-alkanesulfonates where the alkane has from 8 to 22 carbonatoms.

Nonionic surfactants which can be used in practicing the presentinvention can be of three basic types--the alkylene oxide condensates,the amides and the semi-polar nonionics.

The alkylene oxide condensates are broadly defined as compounds producedby the condensation of alkylene oxide groups (hydrophilic in nature)with an organic hydrophobic compound, which can be aliphatic or alkylaromatic in nature. The length of the hydrophilic or polyoxyalkyleneradical which is condensed with any particular hydrophobic group can bereadily adjusted to yield a water-soluble-compound having the desireddegree of balance between hydrophilic and hydrophobic elements.

Examples of such alkylene oxide condensates include:

1. The condensation products of aliphatic alcohols with ethylene oxide.The alkyl chain of the aliphatic alcohol can either be straight orbranched and generally contains from about 8 to about 22 carbon atoms.Examples of such ethoxylated alcohols include the condensation productof about 6 moles of ethylene oxide with 1 mole of tridecanol, myristylalcohol condensed with about 10 moles of ethylene oxide per mole ofmyristyl alcohol, the condensation product of ethylene oxide withcoconut fatty alcohol wherein the coconut alcohol is a mixture of fattyalcohols with alkyl chains varying from 10 to 14 carbon atoms andwherein the condensate contains about 6 moles of ethylene oxide per moleof alcohol, and the condensation product of about 9 moles of ethyleneoxide with the abovedescribed coconut alcohol. Examples of commerciallyavailable nonionic surfactants of this type include Tergitol 15-S-9marketed by the Union Carbide Corporation, Neodol 23-6.5 marketed by theShell Chemical Company and Kyro EOB marketed by The Procter & GambleCompany.

2. The polyethylene oxide condensates of alkyl phenols. These compoundsinclude the condensation products of alkyl phenols having an alkyl groupcontaining from about 6 to about 12 carbon atoms in either a straightchain or branched chain configuration, with ethylene oxide, the saidethylene oxide being present in amounts equal to 5 to 25 moles ofethylene oxide per mole of alkyl phenol. The alkyl substituent in suchcompounds can be derived, for example, from polymerized propylene,diisobutylene, octene, or nonene. Examples of compounds of this typeinclude nonyl phenol condensed with about 9.5 moles of ethylene oxideper mole of nonyl phenol, dodecyl phenol condensed with about 12 molesof ethylene oxide per mole of phenol, dinonyl phenol condensed withabout 15 moles of ethylene oxide per mole of phenol, di-isooctylphenolcondensed with about 15 moles of ethylene oxide per mole of phenol.Commercially available nonionic surfactants of this type include IgepalCO-610 marketed by the GAF Corporation; and Triton X-45, X-114, X-100and X-102, all marketed by the Rohm and Haas Company.

3. The condensation products of ethylene oxide with a hydrophobic baseformed by the condensation of propylene oxide with propylene glycol. Thehydrophobic portion of these compounds has a molecular weight of fromabout 1500 to 1800 and of course exhibits water insolubility. Theaddition of polyoxyethylene moieties of this hydrophobic portion tendsto increase the water-solubility of the molecule. Examples of compoundsof this type include certain of the commercially available Pluronicsurfactants marketed by the Wyandotte Chemicals Corporation.

4. The condensation products of ethylene oxide with the productresulting from the reaction of propylene oxide and ethylene diamine. Thehydrophobic base of these products consists of the reaction product ofethylene diamine and excess propylene oxide, said base having amolecular weight of from about 2500 to about 3000. This base iscondensed with ethylene oxide to the extent that the condensationproduct contains from about 40% to about 80% by weight ofpolyoxyethylene and has a molecular weight of from about 5,000 to about11,000. Examples of this type of nonionic surfactant include certain ofthe commercially available Tetronic compounds marketed by the WyandotteChemicals Corporation.

Examples of the amide type of nonionic surfactants include the ammonia,monoethanol and diethanol amides of fatty acids having an acyl moiety offrom about 8 to about 18 carbon atoms. These acyl moieties are normallyderived from naturally occurring glycerides, e.g., coconut oil, palmoil, soybean oil and tallow, but can be derived synthetically, e.g., bythe oxidation of petroleum, or by hydrogenation of carbon monoxide bythe Fischer-Tropsch process.

Examples of the semi-polar type of nonionic surfactants are the amineoxides, phosphine oxides and sulfoxides. These materials are describedmore fully in U.S. Pat. No. 3,819,528, Berry, issued June 25, 1974, andincorporated herein by reference.

Ampholytic surfactants which can be used in practicing the presentinvention can be broadly described as derivatives of aliphatic amineswhich contain a long chain of about 8 to about 18 carbon atoms and ananionic water-solubilizing group, e.g., carboxy, sulfo and sulfato.Examples of compounds falling within this definition aresodium-3-dodecylamino-propionate, sodium-3-dodecylamino propanesulfonate, and dodecyl dimethylammonium hexanoate.

Zwitterionic surfactants which can be used in practicing the presentinvention are broadly described as internally-neutralized derivatives ofaliphatic quaternary ammonium and phosphonium and tertiary sufoniumcompounds, in which the aliphatic radical can be straight chain orbranched, and wherein one of the aliphatic substituents contains fromabout 8 to about 18 carbon atoms and one contains an anionicwater-solubilizing group, e.g., carboxy, sulfo, sulfato, phosphato, orphosphono.

Cationic surfactants which can be used in practicing the presentinvention include stearyl dimethyl benzyl ammonium chloride, coconutdimethyl benzyl ammonium chloride, cetyl pyridinium chloride and cetyltrimethyl ammonium chloride.

Bleach-stable (i.e., hypochlorite-stable) surfactants which areespecially resistant to oxidation are the alkyl sulfates and paraffinsulfonates. Alkyl sulfates are the water-soluble salts of sulfated fattyalcohols containing from about 8 to about 18 carbon atoms in the alkylgroup. Examples of suitable alcohols which can be employed in alkylsulfate manufacture include decyl, lauryl, myristyl, palmityl andstearyl alcohols and the mixtures of fatty alcohols derived by reducingthe glycerides of tallow and coconut oil.

Specific examples of alkyl sulfate salts which can be employed in theinstant surfactant/dye compositions include sodium lauryl alkyl sulfate,sodium stearyl alkyl sulfate, sodium palmityl alkyl sulfate, sodiumdecyl sulfate, sodium myristyl alkyl sulfate, potassium lauryl alkylsulfate, potassium stearyl alkyl sulfate, potassium decyl sulfate,potassium palmityl alkyl sulfate, potassium myristyl alkyl sulfate,sodium dodecyl sulfate, potassium dodecyl sulfate, potassium tallowalkyl sulfate, sodium tallow alkyl sulfate, sodium coconut alkylsulfate, potassium coconut alkyl sulfate and mixtures of thesesurfactants. Highly preferred alkyl sulfates are sodium coconut alkylsulfate, potassium coconut alkyl sulfate, potassium lauryl alkyl sulfateand sodium lauryl alkyl sulfate.

Paraffin sulfonate surfactants have the general formula RSO₃ M, whereinR is a primary or secondary alkyl group containing from about 8 to about22 carbon atoms (preferably 10 to 18 carbon atoms) and M is an alkalimetal, e.g., sodium or potassium. Paraffin sulfonate surfactants andmethods for their preparation are well known in the art. They may beprepared, for example, by reaction of hydrocarbons with sulfur dioxide,oxygen and a sulfonation reaction initiator. Alternatively, they may beprepared by reacting an alkene and a sodium bisulfite under suitableradiation or catalysis, as disclosed in British Patent 1,451,228published September 29, 1976, and hereby incorporated herein byreference. Paraffin sulfonate surfactants are commercially available,e.g., from Farbwerke Hoechst A.G.

Preferred paraffin sulfonates herein are secondary paraffin sulfonates.Examples of specific paraffin sulfonates herein are:

Sodium-1-decane sulfonate;

Potassium-2-decane sulfonate;

Lithium-1-dodecane sulfonate;

Sodium-6-tridecane sulfonate;

Sodium-2-tetradecane sulfonate;

Sodium-1-hexadecane sulfonate;

Sodium-4-octadecane sulfonate;

Sodium-3-octadecane sulfonate.

Normally, the paraffin sulfonates are available as mixtures ofindividual chain lengths and position isomers, and such mixtures aresuitable for use herein.

Dispensing Means

In order to provide automatic sanitizing of the toilet bowl inaccordance with the present invention, it is essential that thehypochlorite sanitizing agent and the dye, in the form of relativelyconcentrated solutions, be dispensed into the flush water each time thetoilet is flushed.

It is within the contemplation of the present invention that theconcentrated solution of one of the components (i.e., either the dye orthe sanitizing agent) be dispensed into the flush tank during the refillafter a flush (thereby forming a dilute solution of one component in theflush water which is stored in the tank between flushes) and that theconcentrated solution of the other component be dispensed into thistreated flush water during the time it is flowing from the tank to thebowl during the next succeeding flush. Dispensing means which operate todispense solutions into a toilet tank during the time it is refillingare described, for example, in U.S. Pat. Nos. 1,798,090, Lebegue, issuedMar. 24, 1931; 3,339,801, Hronas, issued Sept. 5, 1967; and 3,121,236,Yodro et al., issued Feb. 18, 1964.

It is preferred that both of the concentrated solutions be dispensedinto the flush water on the downflush, i.e., that they be dispensed intothe flush water during the time the flush water is flowing from the tankinto the bowl. In this preferred mode of operation, it is additionallypreferred that the dispensing of the hypochlorite and dye should occurnear the end of the flush in order to avoid wastage of dye andhypochlorite and to keep to a minimum the time of contact between dyeand hypochlorite before they enter the bowl. The respective dispensingmeans for the hypochlorite and dye solutions should preferably bepositioned relative to each other in the toilet tank so that theseconcentrated solutions will be diluted by flush water during the flushbefore they come into contact with each other, i.e., intimate mixture ofstreams of the two concentrated solutions in the flush tank shouldpreferably be avoided. Dispensing means for automatically dispensingsolutions of chemicals into the flush water during the down-flush arewell known to the art. U.S. Pat. No. 3,504,384, Radley et al., issuedApr. 7, 1970, discloses a dual dispenser for separately dispensing adetergent/dye solution and a hypochlorite solution into the flush waterduring the flush. Water from the flush tank flows into the respectivedispenser chambers as the tank fills after a flush, where it comes intocontact with a solid detergent/dye composition and a solidhypochlorite-producing composition in the respective chambers. Duringthe interval between flushes, relatively concentrated solutions of thehypochlorite and detergent/dye compositions form in the respectivechambers, and these solutions are discharged into the flush water on thenext flush. It should be noted that the inlet and outlet ports of thedispenser chambers in the Radley et al. dual dispenser are not closedbetween flushings, and therefore there is opportunity for ingredients inthe respective concentrated solutions in the chambers to diffuse intothe tank water between flushes, whereby there is also opportunity foringredients from one dispenser chamber to ultimately find their way intothe solution in the other dispenser chamber. The longer the timeinterval between flushes, the more likelihood there is that some portionof the contents of the two dispenser chambers will have an opportunityto come into contact with each other before they are dispensed into theflush water on the next flush. While dispensing devices of the typedisclosed in Radley et al. can be used in the method of the presentinvention, they are not preferred. Because of the high reactivitybetween the dye and the hypochlorite, the color intensity and durationof the color signal in the bowl will be less reproducible from one flushto the next than if the dye and sanitizing agent are substantiallycompletely isolated from the tank water (and, therefore, from eachother) between flushes. This isolation can be accomplished in thedispensing means by providing a blocking means such as an air bubble ora mechanical seal which, during the period between flushes, blocks theports by which liquid flows into and out of the dispensing means.Depending on the type dispensing means used, and the materials used inconstructing it, complete isolation of the concentrated solutions fromthe tank water may not always be possible since some small amount ofsolution may escape by capillary action, imperfect sealing of the inletand outlet ports, etc.

Dispensers which completely or substantially completely isolate theircontents from the tank water during the quiescent period between flushesare known to the art and are the preferred type for use in the presentinvention. Such dispensers are disclosed, for example, in U.S. Pat. No.3,831,205, issued Aug. 27, 1974, to Foley; U.S. Pat. No. 3,341,074,issued Sept. 12, 1967, to Panutti; U.S. Pat. No. 4,036,407, issued July19, 1977, to Slone; U.S. Pat. No. 4,171,546, issued Oct. 23, 1979, toDirksing; and U.S. Ser. No. 879,469, Dirksing, entitled PASSIVE DOSINGDISPENSER EMPLOYING TRAPPED AIR BUBBLE TO PROVIDE AIR-LOCK, filed Apr.18, 1978, and abandoned in favor of U.S. Ser. No. 002,524, Dirksing,filed Jan. 11, 1979. All of the foregoing patents and applications areincorporated herein by reference.

Preferably, the amount of sanitizing composition placed in thesanitizing composition dispensing means should be chosen so as to lastat least as long as (i.e., through at least as many flushes as) theamount of dye composition in the dye composition dispensing means. Whenthe consumer no longer sees any color appear in the bowl when flushingthe toilet, this indicates that it is time to replace the system (dyeand sanitizer). Conversely, if the consumer sees that color persists inthe toilet bowl, this is also an indication that the supply ofsanitizing agent has been exhausted and the system should be replaced.As indicated previously, it is undesirable to have a persistent color inthe toilet bowl between flushes, and, therefore, it is preferable thatthe supply of sanitizer last for at least as long as the supply of dye.

The dye and sanitizing agents can be formulated into the form of liquidor solid composition for use in present method. The form of thecomposition will depend upon the type of dispenser used. The mostpreferred dispensers are those which are designed to receive a solidcomposition. With this type of dispenser, water from the flush tankenters into the dispenser during the refill of the flush tank at the endof the flush. Water within the dispenser remains in contact with thesolid composition between flushes, thereby forming a concentratedsolution within the dispenser. When the toilet is flushed, apredetermined amount of the concentrated solution is discharged into theflush water as it flows from the tank to the bowl. Particularlypreferred dispensers which are designed to receive a solid compositionare those of the type disclosed in Dirksing U.S. Pat. No. 4,171,546 andapplication Ser. No. 897,469 supra. In a preferred embodiment, these twotypes of dispensing means are constructed into a dual dispenser unit, asis set forth in Example I, herein.

EXAMPLE I

A solid, compacted sanitizing composition cake was prepared bydry-mixing FORM-2 lithium hypochlorite (30% LiOCl), as available fromLithium Corporation of America, Bessemer City, N.C., with HTH calciumhypochlorite [65% Ca(OCl)₂ ], as available from Olin Mathieson ChemicalCorp., NaCl and Na₂ SO₄ in the proportions hereinafter set forth andsubjecting the granular mixture to a compaction pressure of about 2.5tons per square inch on a Stokes Model R Tablet Press:

    ______________________________________                                        Ingredient              Grams                                                 ______________________________________                                        LiOCl (Form 2)          27.2                                                  HTH [65% Ca (OCl).sub.2 ]                                                                             43.9                                                  NaCl                    21.7                                                  Na.sub.2 SO.sub.4       7.2                                                                           100.0                                                 ______________________________________                                    

This composition had a LiOCl:Ca(OCl)₂ weight ratio of about 0.29:1, andan available chlorine level (AvCl₂) of about 38% to 39%. The cake had aspecific gravity of about 1.7, and dimensions of about 3.5 inches byabout 1.5 inches by about 0.625 inches.

A solid, compacted cake containing dye was prepared by mixing theingredients hereinafter set forth in a batch amalgamator, followed bymilling and then extrusion to form a rectangular slab having dimensionsof about 3.625 inches in width by about 2.0 inches in height by about0.5 inches thick, and a specific gravity of about 1.1.

    ______________________________________                                        Ingredient              Grams                                                 ______________________________________                                        Sodium paraffin sulfonate                                                                             52.2                                                  (Hostapur, approximately                                                      84% active, as available                                                      from American Hoechst,                                                        Somerville, N.J.)                                                             Acid Green 2G Conc.     3.7*                                                  (as available from                                                            Sandoz, Hanover, N.J.)                                                        NaBr                    1.9                                                   Perfume                 7.2                                                                           65.0                                                  ______________________________________                                         *The dye sample contained 10% diluent, therefore, the actual dye level wa     3.3 grams.                                                               

This dye cake was thereafter coated with talcum powder to prevent itfrom sticking to the sides of the dispensing apparatus.

The solid sanitizer cake and dye cake were incorporated, respectively,into separately dispensing compartments of a dual dispensing apparatuswhich was vacuum thermoformed in two segments from 0.015 inch thickpolyvinyl chloride. The configuration of the integrally formed dualcompartment dispenser was such that the dye cake was placed verticallyoverhead the sanitizer cake. The portion of the dispensing apparatushousing the dye cake was of a configuration generally similar to thosedescribed in connection with FIGS. 1 and 15 of the aforementioned patentapplication of Robert S. Dirksing, Ser. No. 897,469, filed Apr. 18,1978, while the portion of the dispensing apparatus housing thesanitizer cake was of a configuration generally similar to thatdescribed in connection with FIG. 12 of the aforementioned patent ofRobert S. Dirksing, U.S. Pat. No. 4,171,546, issued Oct. 23, 1979. Theseseparate portions of the dispensing apparatus (actually two separatedispensing means) produce concentrated solutions, respectively, of thesanitizer composition and dye composition in water which enters theapparatus when the toilet tank is filling after a flush. The respectivedispensing means serve to isolate the concentrated solutions from eachother and from the tank water during the period between flushes,although a very small amount of dye solution was found to migrate intothe flush tank between flushes. The positioning of the respectivedispensing means of the dual dispenser is such as to prevent mixing ofthe dispensed sanitizer and dye solutions during the flush until theyhave been diluted with flush water. The measuring cavity and inletconduit of the sanitizer-containing portion of the dual dispenser is sosized that approximately 9 cubic centimeters of sanitizer-containingsolution is dispensed with each flush cycle of the toilet. Thedye-containing portion of the dispenser is so sized that approximatelytwo cubic centimeters of dye-containing solution is dispensed into theflush water as it leaves the tank during each flush cycle of the toilet.

The aforedescribed exemplary embodiment of a dual dispenser for carryingout the cleansing and disinfecting method of the present inventionprovides an excellent release of both the sanitizer-containing solutionand the surfactant-containing solution throughout the life of the unit.

A conventional toilet comprising a flush tank and a bowl was equippedwith this type dual dispenser by placing the dispenser into the tank.Over a 20-day period the toilet was flushed daily at predetermined timeintervals during each day. Observations of color in the bowl during andafter flushing were made periodically. The toilet was flushed a total of281 times. The first seven flushes are required to prime the dispensingmeans for the hypochlorite sanitizer. Accordingly, on the first sevenflushes very little, if any, hypochlorite was delivered to the bowl, andthe color which was delivered to the bowl persisted between flushes.After the seventh flush, color observations were made on 47 of theremaining flushes. Out of this total of 47 observations, there was oneinstance in which no color was seen in the bowl, either during or afterthe flush was complete. In all other instances color was observed duringthe flush and at the end of the flush. The time of color persistenceranged from 10 seconds to 120 seconds from the end of flush (i.e., fromthe time when the siphon breaks and the bowl begins to refill). Theflush itself takes about 13 seconds (from beginning of tank water flowuntil siphon break), therefore, the total time for color persistence wasfrom about 23 seconds to about 133 seconds. The amount of availablechlorine in the bowl at the end of the flush averaged about 6 ppm.

What is claimed is:
 1. A method of sanitizing a toilet which comprises aflush tank and a bowl, with a hypochlorite sanitizing agent each timethe toilet is flushed, and providing a transitory visual signal toindicate the activity of the sanitizing agent in the bowl, said methodcomprising the step of dispensing, from separate dispensing means, intothe flush water,(A) an aqueous solution of a compound which produceshypochlorite ion in aqueous solution, and (B) a solution of a dyeselected from the group consisting of those identified by Color Indexnumbers 24401 and 42040, and Color Index name Basic Blue 80;the amountof (A) being sufficient to produce a concentration of from about 2 toabout 30 ppm available chlorine in the bowl water at the end of theflush, the amount of (B) being sufficient to produce a dye concentrationof from about 0.02 to about 2 ppm and an available chlorine:dye ratio offrom about 2:1 to about 150:1, and the pH of the solution formed in thetoilet bowl being from about 6 to about
 9. 2. The method of claim 1wherein the respective solutions, (A) and (B), are both dispensed intothe flush water during the down-flush.
 3. The method of claim 2, whereinthe respective solutions, (A) and (B), are substantially completelyisolated from the flush water in the toilet tank during the quiescentperiod between flushes of the toilet.
 4. The method of claim 3 whereinthe amount of sanitizing agent dispensed is sufficient to produce aconcentration of from about 4 to about 8 ppm available chlorine in thebowl water at the end of the flush.
 5. The method of claim 4 wherein theavailable chlorine to dye ratio is from about 5:1 to about 25:1.
 6. Amethod of sanitizing a toilet bowl which comprises a flush tank and abowl, with a bromide-catalyzed hypochlorite sanitizing agent each timethe toilet is flushed, and providing a transitory visual signal toindicate the activity of the sanitizing agent in the bowl, said methodcomprising the step of dispensing, from separate dispensing means, intothe flush water,(A) an aqueous solution of a compound which produceshypochlorite ion in aqueous solution, and (B) a solution comprising adye and a water-soluble bromide salt, the said bromide salt beingpresent in sufficient quantity to catalyze the oxidizing action of thehypochlorite-producing compound of (A) in the bowl, the said dye beingselected from the group of those identified by Color Index numbers24401, 42040, 63010, 42085, 42675, and those having Color Index namesBasic Blue 80, Reactive Blue 17 and Acid Blue 182;the amount of (A)being sufficient to produce a concentration of from about 2 to about 30ppm available chlorine in the bowl, the amount of (B) being sufficientto produce a dye concentration of from about 0.2 to about 2 ppm and anavailable chlorine:dye ratio of from about 2:1 to 150:1 in the bowl, andthe pH of the solution formed in the bowl being from about 6 to about 9.7. The method of claim 6 wherein the dye is Color Index number
 42085. 8.The method of claim 6 wherein the respective solutions, (A) and (B), areboth dispensed into the flush water during the down-flush.
 9. The methodof claim 8 wherein the respective solutions, (A) and (B), aresubstantially completely isolated from the flush water in the toilettank water during the quiescent period between flushes of the toilet.10. The method of claim 9 wherein the amount of bromide salt in (B) issufficient to produce a weight ratio of available chlorine to bromideion of from about 2:1 to about 150:1 in the toilet bowl water at the endof the flush.
 11. The method of claim 9 wherein the amount ofhypochlorite-producing compound dispensed is sufficient to produce aconcentration of from about 4 to about 8 ppm available chlorine in thetoilet bowl at the end of the flush, and the amount of bromide saltdispensed is sufficient to produce a weight ratio of available chlorineto bromide of from about 4:1 to about 13:1.
 12. The method of claim 11wherein the available chlorine to dye ratio is from about 5:1 to about25:1.
 13. The method of claim 12 wherein the dye is Color Index number42085.